1. Field of the Invention
The present invention is in the field of ergonomic supports for seats, especially automobile seats.
2. Prior Art
Ergonomic supports for seats, especially automobile seats that impart a massage type effect on the seat occupant, are known in the art. See, e.g., U.S. patent application Ser. No. 09/536,425, incorporated by reference herein. Typically such prior art massage systems involve an active portion which moves toward and away from a portion of the seat occupant's anatomy to be supported, for example the lumbar spine. The active portion includes a surface that can be put into a variety of selectable positions supporting the spine to a greater or lesser degree. The moving or active portion of the lumbar support is typically a bowing or arching surface movable from a substantially flat position to a substantially bowed position which provides lumbar support.
The prior art devices also require a static portion. For example guide rails—which do not move—provide an anchor along which the active portion can slide or otherwise move through its range of selectable positions.
Alternative designs include push paddle type supports that extend or retract at the end of a linkage or through a channel. See, e.g., U.S. patent application Ser. No. 09/798,657, incorporated by reference herein. Still other options include strap devices that can be tightened or loosened in their relationship with a fixed component in order to move a supporting surface closer or further away from the spine of the seat occupant. See, e.g., U.S. Pat. No. 5,769,490, incorporated by reference herein. Generically, all of these systems have a moving or active portion and a static portion having some type of anchor on which the active portion is mounted and against which it can move to support the load of the seat occupant's weight.
Ergonomic supports for seats have actuating linkages. Frequently these linkages are traction cables such as Bowden cables. Bowden cables are comprised of a conduit containing a wire that slides axially through the conduit (also “sleeve”, or “sheath”) to apply or release traction on the active portion of the lumbar support. The traction moves the active portion into its supporting position and the release of the traction moves the active portion out of its supporting position. For example, in the arching type of ergonomic support the Bowden cable sleeve is mounted to one end of the arching pressure surface of the active portion and the Bowden cable wire is mounted to another end of the active pressure surface. Thereby, traction on the wire draws the two ends of the arching surface towards one another, inducing the arch that supports the seat occupant. Release of the tension allows the arching pressure surface to return to its flat position. Alternative actuating linkages may include rods, wires, rack and pinion devices, compression arrangements, eccentric wheels and the like. See, e.g., U.S. Pat. No. 5,498,063, incorporated by reference herein.
Some prior art lumbar supports cycled automatically through a range of motion. See, e.g., U.S. Pat. No. 6,007,151, incorporated by reference herein.
In the class of lumbar supports known in the art as massage systems, the pressure surface or active portion is modified by having rollers. The rollers are intended to impart a massage type feel to the seat occupant. Accordingly, the active portions are required to support an array of axles or pins on which to mount rollers, along with supporting the array of rollers themselves. The roller arrays in the prior art can be heavy, expensive and cumbersome. Moreover, the additional comfort imparted to the seat occupant by the presence of rollers is often only marginally better than the comfort afforded by the movement of the active portion of the lumbar support in the first place. In some configurations in some seats, empirical evidence indicates that rolling can be eliminated without sacrificing passenger comfort.
The presence of heavy and cumbersome active portions having roller arrays has, in the prior art, required rigid mounting of actuators. Actuators can be manual, but more typically are electrical motors for massaging systems. The actuators generally have an electrical motor operatively engaged with a gear assembly in a housing. The gear assembly typically has a seat or mount for one linkage portion, for example the wire of the Bowden cable, and the housing will have a seat or a mount for another portion of the linkage, for example the Bowden cable conduit. Because a heavy gauge of active portion components is necessary to support an array of rollers, larger motors and actuators are required to move the active portion on prior art massage systems. Moreover, the actuators and motors must be rigidly mounted to the static portion or anchor portion of the ergonomic support. Rigid mounting requires brackets which add further weight and expense.
Seat assemblers consider the “package size” of the entire device to be the widest, tallest and thickest dimensions of the ergonomic support unit as a whole. There is a continuing need in the furniture and automobile seat industry for reducing the total package size and weight, as well as the expense of ergonomic supports. Proliferating comfort systems in seats, such as heating and cooling ducts, require that traditional ergonomic devices such as lumbar supports should be made smaller and lighter. The prior art massage systems were large, heavy and expensive for two primary reasons. Large heavy active portions were required to support an array of rollers, and heavy mounting brackets were used to hold motors and actuators to the static portion of the unit. There is a need in the industry to reduce the weight, size and expense of the roller array on the active portion of a massaging lumbar support, and to reduce the width, thickness and weight of the unit as a whole, particularly by disengaging the actuators from being mounted directly to the static portion of the lumbar support.